Recently I dumped a SS game (Mr. Bones) with 4 audio tracks with exactly the same data. I thought it could be a problem with my CD (scratches or something similar), but a new dump http://redump.org/disc/10661/ has the same issue (tracks 9 and 10). Is it normal?
Yes, it's normal for some discs to have duplicate audio tracks. Why they did that, I have no clue, but I've seen it quite a few times before already.